Changing fuel line without draining tank

[Helirich]

So I got a kit to change all the fuel lines to braided stainless. I did all of them a couple days ago except the line from the filter to the distributor. I had previously changed the filter when the tank was empty. It was kind of a pita. I can imagine it is much worse if fuel was coming out. I want to change that line though, so I got an idea.

What if I jack the rear of the car up high enough that fuel will not syphon? Has anybody done this? How high would it need to go? I'm thinking 18"-24". Not sure if the front will hit the ground with the back up that far. Is there a problem with my plan?

[Michael]

So I got a kit to change all the fuel lines to braided stainless. I did all of them a couple days ago except the line from the filter to the distributor. I had previously changed the filter when the tank was empty. It was kind of a pita. I can imagine it is much worse if fuel was coming out. I want to change that line though, so I got an idea.

What if I jack the rear of the car up high enough that fuel will not syphon? Has anybody done this? How high would it need to go? I'm thinking 18"-24". Not sure if the front will hit the ground with the back up that far. Is there a problem with my plan?

The only fuel you will lose is what's under pressure in the lines and once the pressure(if any) is gone, there's not much that will drain out except the fuel in the lines themselves and that can be mitigated with a rag or drain pan.

Edit: If by any chance you have Dave's RPM relay and if by any chance it has the hot start function turned on and if by any chance you started the car in the hour and half before fuel line replacement and if by any chance the pump primed just as you had a line lose, there is a chance you might lose a few more ounces than normal.

[Helirich]

Are you saying the fuel won't siphon? Why not? The tank is higher than the filter. I'm not sure of the pump construction, but most of them fuel can pass even if their not running. I know there's a check valve in line, but of course it flows that direction.

[Michael]

Are you saying the fuel won't siphon? Why not? The tank is higher than the filter. I'm not sure of the pump construction, but most of them fuel can pass even if their not running. I know there's a check valve in line, but of course it flows that direction.

I wouldn't leave it overnight but in the amount of time it takes to swap out a line, you are not going to lose enough to trouble yourself with.

[DMCMW Dave]

I've changed, and seen changed, dozens if not hundreds of filters (and accumulators come to think of it) on cars that were just running. I have never seen any more gas come out than what was in the filter or lines. I've never seen one siphon. I'm not really sure why it doesn't siphon, but there is probably enough restriction in the pump and check valve that the atmospheric pressure available is too low to start the flow. Also the filter isn't really much lower than the level of the tank.

[Helirich]

I've changed, and seen changed, dozens if not hundreds of filters (and accumulators come to think of it) on cars that were just running. I have never seen any more gas come out than what was in the filter or lines. I've never seen one siphon. I'm not really sure why it doesn't siphon, but there is probably enough restriction in the pump and check valve that the atmospheric pressure available is too low to start the flow. Also the filter isn't really much lower than the level of the tank.

That's great. I don't know why, but I'm glad. When I changed my filter, the tank was drained and I still got a bit of gas out of the lines. I had a tough time getting the filter in and out. I would hate to have gas coming out. On my Bronco the gas just keeps on coming when I change the frame mounted filter.

[Ron]

Fwiw, I have had similar experience as the others -- A few rags will do ya.

If you are really worried about it siphoning, just take the line loose at the pump...

[Helirich]

Fwiw, I have had similar experience as the others -- A few rags will do ya.

If you are really worried about it siphoning, just take the line loose at the pump...

Sounds good. Do any of you guys have the new style pump with the fuel level sensor built in. Just wondering that makes a differnce.

I will have to jack the car up anyways to get access. (I don't have a lift) I do have a gantry crane that could lift it easy if I could figure how to hook it without damage. When I changed the filter, I had the car on jack stands, but it was level. How ever I get it up, I will take some measurements to see if the filter is high enough that it would stop siphon. (If it were possible)

[WHO1DMC]

Sounds good. Do any of you guys have the new style pump with the fuel level sensor built in. Just wondering that makes a differnce.

I will have to jack the car up anyways to get access. (I don't have a lift) I do have a gantry crane that could lift it easy if I could figure how to hook it without damage. When I changed the filter, I had the car on jack stands, but it was level. How ever I get it up, I will take some measurements to see if the filter is high enough that it would stop siphon. (If it were possible)

I have the new style fuel pump and I don't see why it should make a difference.



Dave. B.

[Michael]

Sounds good. Do any of you guys have the new style pump with the fuel level sensor built in. Just wondering that makes a differnce.

I will have to jack the car up anyways to get access. (I don't have a lift) I do have a gantry crane that could lift it easy if I could figure how to hook it without damage. When I changed the filter, I had the car on jack stands, but it was level. How ever I get it up, I will take some measurements to see if the filter is high enough that it would stop siphon. (If it were possible)

:facepalm::rolleyes: